Steve-A

Hi.

I'm fairly new to this so please bear with me.

I've had my 5 for a while now and basically I'd like it to be faster! My car is a 1996 90hp 1.6 mk1, which I bought as it was easiest for me to insure at the time. Once my insurance comes up for renewal, I'll have more NCB, I plan to sell the 90hp car and buy a 115hp car. This wont be till the autumn.

Im the mean time I was reading and investigating about FI routes, and realised the kit for the 1.6 will work on 90hp or 115hp cars. I checked with insurance and after a small top up I'm good to go!

So the plan, as I see it, is to run a basic Greddy kit (picked one up cheap), as it comes from the box, on my 90hp car for a while. Then return the car to standard, sell it, and buy a earlier model and fit the turbo to that.

Thats all fine and dandy. The 30/35hp increase on my 90hp will keep me happy for summer then over the winter I can sort out the more powerful 1990-1993 car.

Turbos in the post, and a boost gauge so I can make sure its doing what its supposed to. I've been reading around here to make sure I'm 100% on the ball before I start the install. I was looknig specifically at the oil routing for the Greddy kit. In the earlier 1.6 models there is both an oil feed and return point on the engine. Alas, as shown in the FAQ, on the later models this is blocked off. As suggested the FAQ I'm planning to use a sandwich plate for the feed.

My question to you guys is if an oil cooler can have feed and return from a sandwich plate, the plates original intention, can my turbo do this too?

I've had a damn good search and couldn't find anything about oil returns, besides the opinion that to tap the sump is better than the Greddy standard return. As I plan to return the car to standard I'd rather not drill the pan if I don't have to. Are there any other ways of routing the oil return?

If tapping the sump is simply the best way to do it then I shall do that, but I just wanted to investigate any other options that might be out there.




Cheers

18psi

iTrader: (76)

1) welcome to the forum
2) you need to make an intro thread in the new members area, update your profile with a location, and update signature with car and specs/mods
3) you will need a bit more than turbo kit and boost gauge to properly tune the turbo kit and have it running well
4) if you read the faq's and search around, there is a greddy kit instructions thread around here that will help you out.
5) as far as I know, tapping the pan is the best/easiest way for oil return, you could either just plug it/weld it up when you return the car back to stock. If you somehow try to route the oil back to the sandwich plate or somewhere else that is not directly beneath the turbo, I suspect the oil will build up in the turbo causing you problems. Either way you look at it I just dont see a better way than tapping the pan. It is proven and easy.
6) while filter sandwich works, there are better ways of getting oil feed to your turbo. read the turbo faq man, there are even pictures there showing you exactly what I'm talking about.

Steve-A

Thankyou for the fast reply. I have updated my location and signature.

I appreciate that to have the turbo running well I could do with more than the basic kit, but from reading other threads I was under the impression that I could run a basic kit at a safe (4/5psi) pressure for the short term. I wanted a boost gauge to keep an eye on the pressure as I thought that the afpr and stock ecu would keep the afr in check as long as it didn't go over 5psi or so.

From the FAQ

I thought that a sandwich plate was just as good as teeing the pressure sender as no preference is stated?

Its fair enough that tapping the pan is the way to go, just thought it was worth asking about any other options.

18psi

iTrader: (76)

the reason the sandwich is not a good idea is because when changing the oil filter you will always have to fumble with the sandwich plate to keep it from coming off with the filter. teeing off the oil pressure sender is just simpler IMO.....neither way is bad, just more of a preference sort of thing

DammitBeavis

Getting the oil pressure to the turbo would be fine with a plate, but why? The T fitting for the oil pressure sensor is right there, just as easy, and they are certainly a lot cheaper than a sandwich plate. As for the oil return, can you really return it to the plate? All the oil in there is going to be under pressure since it's after the oil pump. I'm not sure it's a good idea to pressurize the turbo cartrige. Besides, I'm not sure you would get enough flow.

I know how you feel about tapping the pan though. Even if you're careful it leaves lots of aluminum bits in the pan. However it doesn't appear to have any ill effects since the pieces would have to be small enough to get through the pickup screen, then the filter would grab anything that made it through the pump.

Braineack

iTrader: (62)

I'm trying to remember in the last +15 years of boosted miatas if anyone has had failure from drilling the pan to add a fitting....

Steve-A

Looks like I shall drill the pan and fit a T piece

I realise a t piece would be cheaper, I was just looking into all the options before I started. The FAQ said T piece OR sandwich. Just happened when I looked at sandwiches they talking about flow to and from and oil cooler, and I wondered if it would work. Now I appreciate that the return flow is simply gravity fed I can see why it wont.

Saml01

iTrader: (9)

Why did the earlier cars have more power then the later cars?

I also think what your planning to do is a bit nuts just for the extra 15hp, unless the displacement was different between the years, you can probably get that extra 15 out yourself.

Braineack

iTrader: (62)

The oil cooler is fully pressurized. All the oil travels through the cooler, then back into the motor for use if utilized.

If you connected the outlet of the turbo back to the sandwich plate, the seals in the turbo would fail and you'd leak oil into your intake and exhaust. There should be zero oil pressure in an oil return line off the turbo.

Braineack

iTrader: (62)

Agreed; more trouble than it's worth. 1psi = roughly 10hp. Add a pound of boost and you've just made up the difference.

Steve-A

Once Mazda had introduced the 1.8, when they re-introduced the 1.6 for the uk market they dropped the power to make it more insurable for young drivers. They put the cams from the auto engine, along with lower comp pistons and a slightly more restrictive head on.

The only real reason I was going to change for an earlier car is that on the UK forums I frequent they consider it pointless to bother tuning the 90hp version. The more I read into what the car needs to run higher boost the more I wonder myself whether I'd be better improving my turbo set-up and sticking with the same car.

Braineack

iTrader: (62)

I'm suspect about a different "restrictive" head be used...But if the cams and pistons is true they would be more ideal for boost...


If I were to bother, I'd only go to a 1.8L. I don't even know what Mazda rates my motor at, but it wasn't very hard making 230rwhp out of it under 15psi on a completely stock motor...

Saml01

iTrader: (9)

Steve, you are confusing the **** out of me.

90 - 93, what engine was in the car?
93 -97, what engine was in the car?

I also cast doubt on the restrictive head, cams as well. That would raise the tooling costs for those engines. Lower comp pistons I can believe. If so, then as brainy said, the engine you got would be more suitable for boost.

Steve-A

For the UK market they did...

89-93 1.6 no cat 110 (or so) hp
94-95 1.8 no cat
96-97 1.6 with cat 90hp, and 1.8 with cat.

Then they moved to mk2 in 1998

From what I have read on other forums I'm 100% sure the engine differences from the early to late mk1 1.6s is milder cams and lower comp pistons in the 96-97 engine. I've heard reliable sources say that the head is more restrictive in the 96-97 model too. But these are only things you hear on forums, so it could well be true or false. Mazda's aim wasn't to save cash by using same cams as auto or anything, it was to reduce power to get car into cheaper insurance group. It wouldn't be beyond them to alter the head, but as you say kinda unlikely.

I guess I need to do some more research into the head.

I'm also sure that I should go with the T piece and drilled pan route, and that I will probably look for more boost and keep my car. If 1psi is really 10hp or so then it seems silly to swap the cars for the sake of the cost of a wideband kit, IC and some injectors.....

Braineack

iTrader: (62)

then like i said, the auto cam and pistons are better for boost...keep yours, simple tuning could bring it back up to 110bhp before turbo.

Saml01

iTrader: (9)

If you are planning to pickup a 1.8, it may be worth it to swap. But if you like your car, its in good shape, and you can turn up the boost, then dont bother. Also the cams and lower comp pistons are a plus.

Or, just buy a 1.8 engine and swap it in.

Steve-A

This is quote from another forum (hope this is ok) regarding turboing a 90hp engine.

The previous post to this says, as you guys have said, low comp pistons is good.

That said others had said that they had good returns from their turboed 90hp engines in the same thread. So I'm just gonna take it one step at a time. Even with the drilled pan it doesn't sound like its too much hassle to block it up should I decide that going to earlier model is the only way. Or I suppose I could just source an early head.

I have also found the later 96-97 mk1 has the 4.1:1 diff as in the mk2s rather than the 4.3:1 earlier model diff.

With regards to a 1.8 conversion, at the moment I think it would just be nice to have more than 90hp, the Greddy is in the post so I'll fit it and go from there. I'm sure everyone says this, but its just a bit more power I'm after, I wont become a boost addict..... honest.....

Saml01

iTrader: (9)

I think you made the right choice. The difference in diff is also big, first gear is useless as it is with the 4.1 rear, I cant imagine it with a 4.3.

I still cast major doubt on the head. Where are they getting that info anyway? Are their flow numbers posted somewhere?

Yea, you wont be a boost addict my ***. I said the same thing, the only reason I havent pulled my car apart again is because I just dont have time.

Braineack

iTrader: (62)

1.8L =

1.8L + turbo =

1.6L + JRSC =

1.6L + turbo =


I too would like to see the comparisons of the late 1.6L head to an early model one. With little $$ invested, you could easily make your little 1.6L output 190hp.

Steve-A

Just posting a little update.

I fitted the turbo saturday, and all appears well

In the end, as you guys suggested, I went with a T piece on the oil pressure sender to feed the turbo, and I drilled and tapped the sump for the return. It all went pretty smooth. I had a bit of a problem with my T piece leaking and the oil pressure sender saying I had pressure when the engine was off.... but after a re torque and a bit of contact cleaning, all was well.

Still running in (80miles or so to go before the minimum 300 Greddy suggest) but it feels much more exciting already. Cant wait to open it up properly.

Thanks for the help

I better get working so I can save for a wideband.....